The present application relates generally to high efficiency furnaces and applications utilizing condensation of combustion gases in heating, ventilation, air conditioning and refrigeration systems.
The basic components of a furnace system include a burner, at least one heat exchanger, an air distribution system, and an exhaust. In the burner, gas, such as natural gas or propane, oil or other fuel is delivered and burned to generate heat. A primary heat exchanger transfers heat from the burning gas to the air distribution system. One or more additional secondary heat exchangers may transfer additional heat from the gases from the primary heat exchanger to air in the air distribution system, typically resulting in condensation of the combustion gases. A vent pipe or flue exhausts byproducts of combustion, such as water vapor and carbon dioxide, outside of the space and condensate is drained from the system. The air distribution system, which includes a blower and ductwork, delivers the heated air throughout the space and returns cooler air to the furnace to be heated. High-efficiency gas furnaces, commonly known as condensing furnaces extract so much heat from the flue gas that the water vapor in the flue gas condenses into liquid water, so the furnace produces water as a normal part of its operation. In some cases, if the combustion air to the furnace is not clean, the condensed water or condensate can be corrosive. Materials, such as high-grade stainless steels, that are both corrosion-resistant and heat-resistant, are expensive.
Intended advantages of the systems and/or methods satisfy one or more of these needs or provide other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the claims, regardless of whether they accomplish one or more of the aforementioned needs.